The present invention relates to a combined cooling and lubrication system for an internal combustion engine, in particular a system wherein engine oil performs both the lubrication and cooling function.
It is known to use engine oil for cooling as well as lubrication, as shown in U.S. Pat. No. 2,078,449 issued 27 Apr. 1937 and in U.S. Pat. No. 4,413,597 issued 8 Nov. 1983. It is also known to use engine oil for vehicle cab heating as shown in U.S. Pat. No. 4,449,487 issued 22 May 1984 to Kruger et al. However, the Kruger system requires two separate oil pumps, one for cooling oil and another for lube oil. It is also known to use cooled lube oil to cool charge air to be introduced into the engine, as shown in U.S. Pat. No. 3,102,998 issued Dec. 29, 1964 to Williams. However, in the Williams system all oil which flows through the intercooler must also flow completely through the oil cooler. This requires that the oil cooler have a capacity sufficient to cool all the oil down to the temperature required by the intercooler, which may be a lower temperature than the temperature required for lubrication. Williams does not show using engine oil for both engine cooling and lubricating. It would be desirable to provide a complete engine oil lube and cooling system which provides for both cab heating and for charge air cooling.